Lead (II) nitrate reacts with potassium iodide to form lead (II) iodide and potassium nitrate. How do you write the balanced equation for this?
We must first convert from a word equation to a symbol equation:
The lead (II) ion is represented as
The potassium ion is
In lead (II) iodide, the charges balance in a
Finally, in potassium nitrate, the charges balance in another
The symbol equation is as follows:
The most obvious change we must make, when balancing this equation, is to increase the number of nitrate ions on the right hand side of the equation. We can do this by placing a coefficient of
In doing this we have upset the balance of potassium ions on each side of the equation. Again, we can fix this: we must simply place another coefficient of
Checking over the equations once more, you will notice that we initially had 1 iodide ion on the right hand side, but 2 on the left. However, we already dealt with this in balancing our potassium ions. Now, our equation is balanced.
And that's it! One last thing to add is that you may have noticed the irregularity in iodide ions rather than nitrate ions. In this case, you would have arrived at the same answer simply by working backwards.